In the first detailed analysis comparing the anatomy and behavior of dogs and wolves, researchers found that the facial musculature of both species was similar, except above the eyes. Dogs have a small muscle, which allows them to intensely raise their inner eyebrow, which wolves do not.
“This is a striking difference for species separated only 33,000 years ago and we think that the remarkably fast facial muscular changes can be directly linked to dogs enhanced social interaction with humans.”
Dr Kaminski said: “The evidence is compelling that dogs developed a muscle to raise the inner eyebrow after they were domesticated from wolves.
“Our findings show how important faces can be in capturing our attention, and how powerful facial expression can be in social interaction.”
Dr Kaminski and co-author, evolutionary psychologist Professor Bridget Waller, also at the University of Portsmouth, previously mapped the facial muscular structure of dogs, naming the movement responsible for a raised inner eyebrow the Action Unit (AU) 101.
Anatomist Professor Anne Burrows, of Duquesne University , is a co-author of the paper. She said:
Juliane Kaminski, of the University of Portsmouth, is the study lead author. She said in a statement:
The only dog species in the study that did not have the muscle was the Siberian husky.
The study authors suggest that the inner eyebrow raising movement triggers a nurturing response in humans because it makes the dogs’ eyes appear larger and more infant-like, and also resembles a movement humans produce when they are sad.
Bridget Waller, of the University of Portsmouth, is a study co-author. She told The Guardian:
Researchers compared dogs to their close relatives, wolves. They found that dogs can raise their eyebrows to make a baby-like expression, while wolves can barely move that muscle.
A new scientific study suggests that dogs have evolved to raise their eyebrows to ensnare human empathy. This could be either to emulate babies or to show people the whites of their eyes.
“You don’t typically see such muscle differences in species that are that closely related,” said report co-author Anne Burrows of Duquesne University in Pittsburgh.
Both Burrows and other members of the scientific community have pointed out, however, that the small sample size used in the study means that further research is necessary to back up these findings.
These findings back up similar research carried out in Japan in 2015, which found the brain activity of humans and their personal pets to be similar to that seen between human mothers and their children.
The Evolution Of ‘Puppy Dog Eyes’ | NBC Nightly News
A new scientific study suggests that dogs have evolved to raise their eyebrows to ensnare human empathy. This could be either to emulate babies or to show people the whites of their eyes.
This makes their eyes appear bigger and more closely resemble human infants, triggering a nurturing response in people.
Researchers compared dogs to their close relatives, wolves. They found that dogs can raise their eyebrows to make a baby-like expression, while wolves can barely move that muscle.
“You don’t typically see such muscle differences in species that are that closely related,” said report co-author Anne Burrows of Duquesne University in Pittsburgh.
The scientists believe that these muscles were developed almost entirely because it gave them an advantage with humans. People have been documented to focus almost entirely on the upper areas of the face while communicating, and the dogs could be responding to that.
These findings back up similar research carried out in Japan in 2015, which found the brain activity of humans and their personal pets to be similar to that seen between human mothers and their children.
Another hypothesis in the paper is that the dogs raise their eyebrows to show the white sclera of their eyes, a trait that humans share and find appealing. Most mammals have darker sclera to conceal the direction of their gaze.
Both Burrows and other members of the scientific community have pointed out, however, that the small sample size used in the study means that further research is necessary to back up these findings.